C13

Question 1

What caused the oxygen levels to increase on Earth?

Answer 1

As plants and algae began to form in the oceans, they would make their own food through photosynthesis by using the energy from the Sun. This produced oxygen gas as well as removing carbon dioxide from the atmosphere.

Question 2

The early atmosphere contained a lot of water vapor. Where did it go?

Answer 2

As the Earth cooled down, it condensed to form the oceans

Question 3

Which process removed carbon dioxide from the atmosphere?

Answer 3

The formation of sedimentary rocks removed carbon dioxide from the atmosphere

Question 4

Why did nitrogen build up in the atmosphere?

Answer 4

It is unreactive

Question 5

How were crude oil and natural gas formed?

Answer 5

From the remains of plankton deposited in muds on the seabed.
These remains were covered sediments that became layers of rock when compressed over millions of years.

Question 6

What are greenhouse gases?

Answer 6

Gases that directly contribute to the greenhouse effect

Question 7

What are the 3 main greenhouse gases?

Answer 7

• Water vapor
• Methane
• Carbon dioxide

Question 8

What is global warming?

Answer 8

The increase in the average temperature of the Earth’s atmosphere globally

Question 9

Why is there an increase of greenhouse gases in the atmosphere?

Answer 9

• Burning fossil fuels in vehicles releases carbon dioxide
• Farming cattle releases methane
• Deforestation releases carbon dioxide

Question 10

Why is global warming difficult to prove?

Answer 10

There are so many factors to consider and many tests can be biased

Question 11

How was ammonia and methane removed?

Answer 11

It reacted with oxygen formed by algae and plants
CH4 + 2O2 –> CO2 + 2H2O
4NH3 + 3O2 –> 2N2 + 6H2o

Question 12

What is carbon footprint?

Answer 12

The carbon footprint of a product, service, or event is the total amount of carbon dioxide and other greenhouse gases emitted over its full cycle.

Question 13

3 consequences of rising levels of greenhouse gases

Answer 13

• Rising sea levels due to melting ice caps in the Arctic
• Increase in global average air temperatures
• Increasingly common extreme weather events

Question 14

Why is the greenhouse effect necessary for life on Earth?

Answer 14

Greenhouse gases are crucial to keeping our planet at a suitable temperature for life. Without it, the Earth would be too cold for life to exist.

Question 15

What actions can be taken to reduce a carbon footprint?

Answer 15

• Carbon taxes
• Carbon capture and storage
• Increased use of alternative energy

Question 16

What are the problems of reducing the carbon footprint?

Answer 16

• Incomplete international cooperation
• Lack of public information and education
• Scientific disagreement over climate change
• Economic limitations

Question 17

How is carbon monoxide released?

Answer 17

By incomplete combustion of carbon in fuel

Question 18

What are the issues regarding sulfur dioixde and nitrogen oxides?

Answer 18

They cause respiratory problems in humans and cause acid rain which damages plants

Question 19

Why is carbon monoxide harmful?

Answer 19

It is an odorless and colourless toxic gas that binds to haemoglobin in the blood, reducing the amount of oxygen provided to the body’s vital organs

Question 20

What are the 4 main atmospheric pollutants?

Answer 20

Carbon monoxide, sulphur dioxide, nitrogen oxide and particulates

Question 21

What is used to analyze gas levels in the Earth’s atmosphere thousands of years ago?

Answer 21

Ice cores which have gases trapped inside them from thousands of years ago

Question 22

How is nitrogen oxide released into the atmosphere?

Answer 22

Through the oxidation of nitrogen in air at high temperatures in vehicle engines

Question 23

Why is nitrogen oxide harmful?

Answer 23

The toxic gas can inflame the lining of the lungs and trigger asthma attacks

Question 24

What are the advantages of complete combustion compared to incomplete combustion?

Answer 24

• Less soot (carbon particulates) released
• Carbon monoxide is not produced
• More energy is released

Question 25

How are particulates harmful?

Answer 25

• Can cause cancer
• Damage cells
• Cause global dimming

Question 26

How are particulates released?

Answer 26

When hydrocarbon molecules don’t burn completely

Question 27

Where did the carbon dioxide in the early atmosphere come from?

Answer 27

Volcanic activity

Question 28

At what temperature on Earth, would oceans have started to form?

Answer 28

100 degrees Celsius

Question 29

How does heating limestone release carbon dioxide?

Answer 29

Limestone or calcium carbonate breaks down into calcium oxide and carbon dioxide when heated

Question 30

Scientists do not know the accurate composition of the Earth’s early atmosphere. Suggest why.

Answer 30

Humans had not evolved as it was billions of years ago

Question 31

Oxidation of hydrogen

Answer 31

Hydrogen + Oxygen —> Hydrogen Oxide (H2O) also known as water

Question 32

Suggest two reasons why the world production of coal is predicted to increase

Answer 32

• Many countries have coal as oil is running out
• It is easy to find and extract

Question 33

There is not much oxygen in the atmosphere of Mars. Suggest why.

Answer 33

Mars has no plants or trees

Question 34

The percentage of argon in the Earth’s atmosphere today is the same as it was in the Earth’s early atmosphere. Suggest why

Answer 34

Argon is unreactive/inert as it is a noble gas

Question 35

What colour is universal indicator in a solution of sulfur dioxide?

Answer 35

Red / orange / yellow, because it is an acid

Question 36

When was Earth formed?

Answer 36

4.6 billion years ago

Question 37

What % of the atmosphere is nitrogen?

Answer 37

78%

Question 38

What % of the atmosphere is oxygen?

Answer 38

21%

Question 39

What % of the atmosphere is carbon dioxide?

Answer 39

0.04%

Question 40

What % of the atmosphere is argon?

Answer 40

0.9%